National Forensic Doctor

There are many ways to identify a circuit board as identical, the simplest being to check the serial number and manufacturer's logo.

On this point, after Huawei launched its new CPU, many self-media companies adopted this idea. However, if the manufacturer or assembler deliberately conceals it, erodes the serial number and logo, or it is missing due to explosion, fire or other reasons, the effect of this method is very limited.

Compared with checking the serial number and manufacturer's logo, a slightly more complicated solution is to scan the characteristics of the circuit board, or simply use image recognition technology to make the identification. This technology sounds very awesome, but in fact it is very sparse to use. Technology. Basically, it can only be used inside the factory. Outside the factory, in the field of criminal investigation, the problem of a database will kill people.

In the real world, there are many ways to identify various traces and identify them as identical. What really hinders technological progress is actually database technology.

Including the identification of footprints, shoe prints, palm prints, firearms, DNA, mitochondrial DNA, tire tracks, etc., all face database problems.

The software is easy to make, but the data in the database really requires the police to enter it one by one.

Over the years, that is, the database entry of fingerprints and DNA, there is a certain guarantee. Other types of databases are basically in a state of enclosure and are definitely not easy to use.

Therefore, Jiang Yuan has used the technology of scanning circuit board features before, and it is certain that it will not work.

In the end, Jiang Yuan was still arranging and combining components one by one. In technical terms, it means observing the arrangement of specific components and connectors.

Circuit boards of the same model can have similar components and connectors, but circuit boards produced by different manufacturers still have differences in the location and layout of different components.

In addition, it can be easily imagined that the circuit boards produced by different manufacturers and the components purchased are definitely different. And many components are also marked and may not necessarily be erasable.

The circuit board picked up by the survey team was already in a tattered state, so in the end, the model of the circuit board could only be determined through the components themselves and the arrangement and combination of the components - the first step was to determine the manufacturer of the circuit board. , for most trace inspections, after completing this step, the work is roughly completed.

In most cases, the police go directly to the manufacturer and ask the manufacturer's technicians to determine the model of the wreckage. The method is still the same, except that the manufacturer's pictures are more complete and the personnel are more familiar with their own circuit boards.

Jiang Yuan was similar, but after confirming the manufacturer, he sent someone directly there, and then searched the manufacturer's computer for the same model and checked the manufacturer's sales records on the spot.

Then, the police officers flew to several sellers to extract and investigate further sales records.

Three days later.

At 3:30 in the morning, the ringing of the phone woke Zhang Dinghui from his dream.

Zhang Dinghui sat up, everyone was confused.

The person next to the pillow also turned over and looked at his watch, and said helplessly: "Are there so many things happening recently?"

"As long as it's not a bad thing." Zhang Dinghui shook his head and answered the phone: "I'm Zhang Dinghui..."

"...We have determined the location of the suspect." On the other end of the phone was Deng Jiabin, the director of the Municipal Bureau.

Zhang Dinghui suddenly woke up: "Did you confirm the location directly?"

He also went to investigate again yesterday. To be honest, it was the Supervisory Army. At that time, it was still under investigation and there was no news about the suspect at all.

"Yes." Director Deng Jiabin responded and said: "When the suspect purchased circuit boards, he used cash, but the store owner's cash register has time records. We found a card with a human figure where the suspect was walking that day. At the intersection at the entrance, I contacted the shop owner to confirm the suspect’s identity.”

Zhang Dinghui is actually very familiar with these investigative methods. Hearing this, he said "hmm" and his expression became more solemn. He asked: "Who is the suspect? How does he know the relevant technology?"

"The suspect Ji Haitao is a farmer and is 68 years old. The techniques for making explosives should have been learned during militia training. In addition, he has a record of using external networks and should have learned some related techniques." Deng Jiabin answered He was very direct, telling the main content first, and then said: "This Ji Haitao worked as a construction worker and fired artillery in the mine. Later, he also led an engineering team. The purpose of committing the crime this time is very likely to be a conspiracy. fiscal."

Zhang Dinghui breathed a sigh of relief. The suspect who was looking for money should not be so anti-social. What he was most afraid of was that the other party would cause explosions for no reason. This was what he was most worried about these days. .

Deng Jiabin knew the leader's thoughts well, and continued: "We initially judged that the deceased wearing an explosive vest was Ji Haitao's accomplice. Judging from the descriptions of witnesses at the scene, the two entered the finance room at that time. They should have wanted to use the explosive vest to It was a robbery, but we currently have no way of knowing whether money was taken and why the explosive vest exploded."

Zhang Dinghui said "hmm" again. Even if the 68-year-old criminal suspect is in good health, it would be very difficult for him to rob a gambling house alone, and it would not be easy to control another person. An accomplice is indeed a reasonable guess.

"Does he still have explosives in his hand?" Zhang Dinghui asked.

Deng Jiabin: "In this regard, we are similar to our previous speculation. There should still be some. However, Ji Haitao has not shown a tendency to make homemade explosives. He mainly obtains materials through some channels. From this perspective, the explosives in his hands are It shouldn’t be too much. In addition, Ji Haitao’s economic conditions are relatively average, and the explosives he used this time may even have been accumulated in the past.”

Zhang Dinghui knew that Deng Jiabin was trying to comfort him, but his mood did feel relieved. Looking at his wife who was sleeping restlessly next to him, Zhang Dinghui got up and took the phone. As he walked out, he asked in a deep voice: "How are you going to arrest the suspect? What is the situation at the scene?"

"The house Ji Haitao rents is in the Anyuewan community on the outskirts of the city. It is a 28-story high-rise residential building with a tower structure and a small apartment. There are many neighbors above and below, and there are 6 households on the same floor, all of which are full. One of them is full. The room is shared by several people. There should be more than 20 people on a single floor." Deng Jiabin only mentioned the residents on the same floor, not those upstairs, which made Zhang Dinghui feel a strong sense of crisis.

"We can't arrest him inside the house." Zhang Dinghui said flatly: "Either trick him into trapping him...or see what other plans you have."

Zhang Dinghui was already relatively open-minded and did not directly give a direction for his subordinates to take. Even so, he definitely rejected the idea of ​​arresting people inside the residence.

Deng Jiabin also expected this. Although at this point in time, it is still a plan to secretly send people to sneak into the suspect's house and arrest him, but the danger of this plan is also unquestionable.

Even with the bonuses of various advanced instruments, such as thermal imaging cameras, night vision devices and other equipment, you can't fully understand how the suspect placed and handled the explosives.

What if this person has some delusions of victimization - which can't be considered delusions now - and if he gets some strange switches or tricks for explosives, or even makes a booby trap on the door, it will be a big problem.

However, it may not be that easy to deceive people.

Deng Jiabin didn't dare to guarantee it, so he could only say: "I will go to the scene to direct now and convey your instructions clearly!"